Polymerization of epoxides



3,085,071 POLYMERHZATHON F EPQXEDES Frederick E. Bailey, .lr., Charleston, W. Va, assignor to Union Carbide Corporation, a corporation of New York No Drawing. Filed Mar. 2, 1950, Ser. No. 12,261 12 Claims. (Cl. 260-2) This invention relates to a process for polymerizing epoxide compounds.

In a broad aspect the instant invention is directed to the process for polymerizing vicinal-epoxy hydrocarbon free of unsaturation other than aromatic unsaturation in contact with a catalytically significant quantity of certain divalent metal sulfites described hereinafter to produce useful polymers.

It is deemed appropriate at this time to define the term reduced viscosity since this term will be employed in the disclosure. By the term reduced viscosity, as used herein including the appended claims, is meant a value obtained by dividing the specific viscosity by the concentration of the polymer in the solution, the concentration being measured in grams of polymer per 100 milliliters of solvent at a given temperature. The reduced viscosity value is regarded as a measure of molecular weight. The specific viscosity is obtained by dividing the difference between the viscosity of the solution and the viscosity of the solvent by the viscosity of the solvent. Unless otherwise indicated, the reduced viscosity value is determined at a concentration of 0.2 gram of polymer per 100 milliliters of solvent, i.e., acetonitrile at 30 C.

Accordingly, one or more of the following objects will be achieved by the practice of this invention.

It is an object of this invention to provide a novel' process for polymerizing vicinal-epoxy hydrocarbon free of unsaturation other than aromatic unsaturation in contact with a catalytically significant quantity of certain divalent metal sulfites to produce useful polymers. It is also an object of this invention to provide a novel process for polymerizing an admixture containing two or more different vicinal-epoxy hydrocarbons which are free of unsaturation other than aromatic unsatu-ration in contact with a catalytically significant quantity of certain divalent metal sulfites as catalysts therefor. Another object of this invention is to prepare solid polymers in accordance with the teachings herein set forth. A further object of this invention is directed to the preparation of resinous poly(ethylene oxide). Other objects will become apparent to those skilled in the art in the light of the instant specification.

The vicinal-epoxy hydrocarbons. free of unsaturation other than aromatic unsaturation which can be employed in the polymerization process of the invention can be characterized by the following formula:

wherein each R individually, can be hydrogen or a hydrocarbon radical free from ethylenic and acetylenic unsaturation such as, for example, alkyl, aryl, cycloalkyl,

aralkyl, or alkaryl radicals. In addition, both R Variables together -with the epoxy carbon atoms, i.e., the carbon atoms of the epoxy group,

can represent a saturated cycloaliphatic hydrocarbon nucleus containing from 4 to carbon atoms, preferably from 4 to 8 carbon atoms, such as, for example,

3,085,071 Patented Apr. 9, 1 963 ice a nucleus derived from cycloalkane, alkyl-substituted cycloalkane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, Z-methylcyclopentane, 3-amylcyclohexane, and the like. Illustrative R radicals include, among others, methyl, ethyl, propyl, butyl, isobutyl, hexyl, isohexyl, 3-propylheptyl, dodecyl, octadecyl, phenyl, benzyl, tolyl, xylyl, ethylphenyl, butylphenyl, phenethyl, phenylpropyl, cyclopentyl, cyclohexyl, Z-methylcyclo- 'hexyl, cycloheptyl, and the like.

Illustrative vicinal-epoxy hydrocarbons which can be employed in the polymerization process of this invention include, for example, ethylene oxide, propylene oxide, 1,2-epoxybutane, 2,3-epoxybutane, the epoxypentanes, the epoxyhexanes, the epoxyheptanes, 2,3-epoxyheptane, 5- butyl-3,4-epoxybutane, 1,2-epoxydodecane, 1,2-epoxyoctade-cane, styrene oxide, ortho-, meta-, and para-ethylstyrene oxide, the oxabicycloalk'anes, e.g., 7-oxabicyclo- [4.1.0]l1eptane, 6-oxabicyclo [3.1 .0] hexane, 4-propyl-7- oxabicyclo[4.l.0]heptane, and the like. The lower olefin oxides, that is, ethylene oxide, propylene oxide, and the epoxybutanes are especially suited to prepare high molecular weight products. A single vicinal-epoxy hydrocarbon or an admixture of at least two different vicinal-epoxy hydrocarbons can be employed as the monomeric feed. In polymerizing an admixture comprising two different vicinal-epoxy hydrocarbons, it is preferred that one of them be a lower olefin oxide.

The catalysts which can be employed in the polymerization process are the sulfites of divalent metals which have an atomic number greater than 11 and less than 57 of group II of the periodic table. These divalent metal sulfites include magnesium sulfite, calcium sulfite, zinc sulfite, strontium sulfite, cadmium sulfite, and barium sulfite. The alkaline earth metal (Ca, Sr, and Ba) sulfites are preferred; calcium sulfite is especially preferred.

The catalysts are employed in catalytically significant quantities, and, in general, a catalyst concentration in the range of from about 0.1, and lower, to about 10.0 weight percent, and higher, based on the total weight of monomeric material, is suitable. A catalyst concentration of from about 0.3 to 5.0 weight percent is preferred. For optimum results, the particular catalyst employed, its surface area, the nature of the monomeric reagent(s), the operative temperature at which the polymerization reaction is conducted, and other factors will largely determine the desired catalyst concentration.

The polymerization reaction can be effected over a wide temperature range. In general, a reaction temperature in the range of from about 50 C., and lower, to about 150 C., and higher, is suitable. A reaction temperature in the range of from about 70 C. to about C. is preferred. As a practical matter, the choice of the particular temperature at which to effect the polymerization reaction depends, to an extent, onthe nature. of he vicinalepoxy hydrocarbon reagent(s) and particular catalyst employed, the concentration of the catalyst, and the like.

In general, the reaction time will vary depending .on the operative temperature, the nature of the vicinal epoxy hydrocarbon reagent(s) employed, the particular catalyst and the concentration employed, the choice and amount of an inert, normally-liquid organic vehicle, and other factors. The reaction time can be as short as a few hours in duration or it can be as long as several days.

When polymerizing an admixture containing two different vicinal-epoxy hydrocarbons, the proportions of said vicinal-epoxy hydrocarbons can vary over the entire range. Preferably the concentration of either monomeric vicinal-epoxy hydrocarbon is in the range of from about the liquid phase. Preferably, the polymerization reaction is conducted under an inert atmosphere, e.g., nitrogen. It is also desirable to effect the polymerization process under substantially anhydrous conditions.

The polymerization reaction can be carried out in the presence of an inert normally-liquid organic vehicle such as, for example, aromatic compounds, e.g., benzene, toluene, xylene, ethylbenzene, chlorobenzene, and the like; various oxygenated organic compounds such as anisole, the dimethyl and diethyl ethers of ethylene glycol, of propylene glycol, of diethylene glycol and the like; normally liquid saturated hydrocarbons including the open chain, cyclic, and alkyl substituted cyclic saturated hydrocarbons such as pentane, hexane, heptane, various normally-liquid petroleum hydrocarbon fractions, cyclohexane, the alkylcyclohexanes, decahydronaphthalene, and .the like.

An induction period may be observed in that the polymerization is not initiated immediately. The induction period can be as short as minutes in length with the more active catalysts or it can be several hours in duration. This induction period depends, for example, on the individual catalyst employed, its preparation, its surface area, the nature of the monomeric feed, the reaction temperature, the purity of the monomeric feed, and other factors.

Unreacted monomeric reagent can be recovered from the reaction product by conventional techniques such as distillation. If desired, the polymer product can be washed with an inert, normally-liquid organic vehicle, e.g., pentane, heptane, etc., in which the polymer product is insoluble and the monomeric reagent is soluble. The washed polymer product can then be recovered, dried in a vacuum, e.g., about to 50 mm. of Hg, at elevated temperatures, e.g., about 30 to 45 C. Another route involves dissolution in a first inert, normallyliquid organic vehicle, followed by addition of a second inert, normally-liquid organic vehicle which is miscible with the first organic vehicle but which is non-solvent for the polymer, thus resulting in precipitating the polymer product. The precipitated polymer is readily recovered by filtration, decantation, etc., followed by drying same under reduced pressure at slightly elevated temperatures.

The products of the polymerization process are valuable and useful polyethers. The viscous liquid to Wax-like polymers can be employed as solvents, raw materials and plasticizing agents for resins, and the like. The solid polymers are useful for the production of various shaped articles. The polymers are also useful as lubricants, vehicles, and intermediates in industries such as the food, pharmaceutical, textile, and petroleum industries. Resinous ethylene oxide polymers are useful as sizing agents, coagulants, and water-soluble lubricants. The watersoluble and water-insoluble solid polymers are also useful in the preparation of films by conventional techniques such as by milling on a two-roll mill, calendering, solvent casting, and the like.

The following examples are illustrative.

Example 1 To a Pyrex glass tube maintained under a nitrogen atmosphere, there were charged 30 grams of ethylene oxide and 0.9 gram of calcium sulfite. The tube was sealed and then inserted into an aluminum block which was gently agitated for a period of 92. hours at 90 C. At the end of this period of time the tube was broken and the polymer recovered therefrom. There were obtained 30 grams of a tough, water-soluble polymer which had a reduced viscosity value of 2.37 in acetonitrile.

In an analogous manner, propylene oxide can be homopolymerized in the presence of 0.5 weight percent magnesium sulfite, under the operative conditions noted above, to give a water-insoluble polymer.

d Example 2 To a Pyrex glass tube maintained under a nitrogen atmosphere, there were charged 30 grams of ethylene oxide and 0.9 gram of calcium sulfite. The tube was sealed and then inserted into an aluminum block which was gently agitated for a period of 92 hours at C. At the end of this period of time the tube was broken and the polymer recovered therefrom. There were obtained 30 grams of a hard, water-insoluble polymer which had a reduced viscosity value of 1.27 in acetonitrile.

In an analogous manner, 1,2-butylene oxide can be homopolymerized in the presence of 1.0 weight percent zinc sulfite, under the operative conditions noted above, to give a water-insoluble polymer.

Example 3 To a Pyrex glass tube maintained under a nitrogen atmosphere, there is charged 30 grams of propylene oxide and 0.9 gram of calcium sulfite. The tube is sealed and then is inserted into an aluminum block which is gently agitated for a period of 50 hours at C. At the end of this period of time the tube is broken and the polymer is recovered therefrom. There is obtained a water-insoluble polymeric product.

In an analogous manner, an admixture containing 80 parts by weight of ethylene oxide and 20 parts by weight of propylene oxide can be copolymerized in the presence of 2 parts by Weight of barium sulfite, under the operative conditions noted above, to give a water-soluble polymeric product.

Example 4 To a Pyrex glass tube, there is charged 30 grams of 1,2-epoxybutane and 0.9 gram of calcium sulfite. The tube is sealed and then is inserted into an aluminum block which is gently agitated for a period of 72 hours at 90 C. At the end of this period of time the tube is broken open and the polymeric product is recovered therefrom. There is obtained a water-soluble polymeric product.

In an analogous manner, an admixture containing 85 parts by weight of ethylene oxide and 15 parts by weight of cyclohexene oxide can be copolymerized in the presence of 3 parts by weight of calcium sulfite, under the operative conditions noted above, to give a solid, watersoluble copolymer.

Although the invention has been illustrated by the preceding examples, the invention is not be construed as limited to the materials employed in the above-said exemplary examples, but rather, the invention encompasses the generic area as hereinbefore disclosed. Various modifications and embodiments of this invention can be made without departing from the spirit and scope thereof.

What is claimed is:

1. A process which comprises contacting a vicinalepoxy hydrocarbon characterized by the following formula:

wherein each R individually, is selected from the group consisting of hydrogen, a hydrocarbon radical free from ethylenic and acetylenic unsaturation, and a portion of a saturated cycloaliphatic hydrocarbon nucleus which nucleus contains from 4 to 10 carbon atoms including both epoxy carbon atoms shown in the above formula; with from about 0.1 to about 10.0 weight percent, based on the weight of said vicinal-epoxy hydrocarbon, of a divalent metal sulfite, the divalent metal portion of which is selected from the group consisting of magnesium, calcium, zinc, strontium, cadmium, and barium; at a temperature in the range of from about 50 to about C., and for a period of time sufficient to produce a polymer.

2. The process of claim 1 wherein said vicinal-epoxy hydrocarbon is a lower olefin oxide.

3. The process of claim 2 wherein said catalyst is an alkaline earth metal sulfite.

4. The process of claim 3 wherein said catalyst is calcium sulfite.

5. The process of claim 2 wherein said catalyst is zinc sulfite.

6. The process of claim 2 wherein said catalyst is magnesium sulfite.

7. A process which comprises contacting an admixture containing ethylene oxide and a lower olefin oxide with from about 0.1 to about 10.0 weight percent, based on the total weight of said ethylene oxide and said lower olefin oxide, of a divalent metal sulfite, the divalent metal portion of which is selected from the group consisting of magnesium, calcium, zinc, strontium, cadmium, and barium; at a temperature in the range of from about 50 to about 150 C., and for a period of time suflicient to produce a polymer.

8. The process of claim 7 wherein said lower olefin oxide is propylene oxide.

9. A process which comprises contacting ethylene oxide with a catalytically significant quantity of a divalent metal sulfite, the divalent metal portion of which is selected from the group consisting of magnesium, calcium, zinc, strontium, cadmium, and barium; at a temperature in the range of from about 70 to about 120 C., and for a period of time sufficient to produce solid poly(ethylene oxide).

10. The process of claim 9 wherein said catalyst is an alkaline earth metal sulfite.

11. The process of claim 10 wherein said catalyst is calcium sulfite.

12. The process of claim 9 wherein said catalyst is magnesium sulfite.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A PROCESS WHICH COMPRISES CONTACTING A VICINALEPOXY HYDROCARBON CHARACTERIZED BY THE FOLLOWING FORMULA: 